Absorption refrigeration



Oct. 9, 1934. K. v. NEssELMANN 1,975,860

ABSORPTI ON REFRIGERATION Filed May 25, 1935 patented ct. 9,1934A .ETED STATES ABsonP'rIoN" nEFnIGEaATioN V. Nessclmann, Berlin-Siemensstadt, Germany, assigner to The Hoover Company, North `Canton, Ohio, a corporation of Ohio Application May 25, 1933, Serial No. 672,74

In Germany February 13, 1932 s claims. (ci. se-iias) This invention relates to refrigerating apparatus and more particularly to systemsl of the type in which inert gas is employed as a pressure equalizing medium so thatrefrigeration may be a produced although the total pressure in the system is substantially the same throughout but the partial pressure of the refrigerant diiers in different parts so as to enable the refrigerant to evaporate'and produce a cooling Yedect in one i@ part at a lower temperature than that at which it is changed to a more dense phase in another part of the system.

This particular invention involves improvements in a system of the type in which an absorption liquid is circulated through a number of vessels, some of which have an inert gas therein and others of which do not, and some of which operate at higher temperature than others. An example of sucha system is disclosed in the copending application of Donald G. Smellie, Serial No. 490,497 led October 22, 1930- for Absorption refrigeration. e An object of the present invention is to devise improved means and methods for carrying out the principle disclosed in the aforesaid Smellie application, and for effecting certaineconomies therein.'

Another object of the invention is to provide a refrigerating system of the type referred `isb in which improved means is used for circulating the absorption liquid through the various vessels.

Other objects and advantages reside in certain novel features of the arrangement and construction of parts aswill be apparent. from the following description taken in connection with the vaccompanying drawing in which,

The single gure is a diagrammatic representation oi an absorption refrigerating system constructed in accordance with the principles of the ao present invention.

Referring to the gli drawing in detail, reference character 1 designates a boiler of the usual construction, which may be heated by an electric cartridge heater to cause refrigerant gas to be driven on from an absorption liquid therein. The gas so expelled may pass upwardly through a conduit 3 provided with heat radiating ns 4 so vas to cause the vertical section of the pipe 3 to act as a rectier.

At the point 5 the gas conduit 3 joins vthe gas conduits 6 which extends downwardly and unites with the right hand leg of a U-shaped conduit 7, at about the mid-portion of the leg. Conduit 7 v conveys absorption liquid from the absorber 8 to a coil 9 located in a heat exchange vessel 10. The

upward end of the coil 9 is connected by a conduit 11 with a reversely bent pipe 12 provided with heat radiating iins, the pipe 12 being in turn connected to a small gas separating chamberA 13. Absorption fof gas takes place in `the right hand leg ofthe conduit 7 (above the point of connection of gas conduit 6), the coil 9, the conduit 11 the bent pipe 12 and possibly to some extent in the vessel 13. These elements are thus component vpartsof what may be called a resorber. 65

The U-.shaped conduit 14 may convey absorption liquid from the vessel 13 into the evaporator 15, which is shown as provided with ns on the outlside and with a number of baies 16 on the inside thereof, thelatter acting to retain a portion of the absorption liquid therein. A conduit 17 is provided to convey absorption solution from the bottom of the evaporator into heat exchange relation `with a portion of the conduit 14 as illustrated, and into the heat exchange vessel 10.

Inasmuch as the liquid supplied to the vessel '10 by the conduit 17 is heated by the coil 9 in that vessel, some gas will be expelled therefrom which will pass off through the conduit 18 and join that gas coming from the boiler through the conduit 3 as the junction point 5, this gas then owing downwardly through the conduit 6 into the pipe 7 and upwardly through the coil 9.

The boiler 1 has a number of conduits connected thereto in addition to the gas conduit 3; A liquid conduit 19 connects the bottom of the boiler to the top of absorber 8, the portion of the conduit y 19 adjacent the boiler being U-shaped and joining a small conduit 20 connected to the vtop of the boiler. As it leaves conduit 20 the conduit 90 19 passes downwardly, in heat exchange relation with the conduit 7 and upwardly to enter the top of the absorber 8. Liquid may thus flow from the boiler'l to the top of the absorber 8 through the conduit 19. In the absorber, after trickling down over the baille plates'therein, the liquid co1- lects in the lower portion of the absorber.

The absorber is connected to the evaporator by two large gas conduits 20 and 21, the conduit 20 `being adapted to convey gas from the top of the 109 absorber lto the top of the evaporator, while the conduit 21 provides fr the iiow of gas from the evaporator to the lower` portion ofv the absorber beneath the baille plates thereof.

In addition to the baille-plates, the absorber is 10.5 provided with a small cylindrical member 22 situated just below the entrance of the conduit 21 which causesv the formation of a slight seal therein so that gas coming from the small gas separating chamber 13 through the conduit 23 may bubble 110 novaaeo upwardly through the liquid collected around the cylinder 22, this seal preventing the how of inert gas from the absorber into the gas separating chamber 13 through the conduit 23.

ln addition to the aforesaid conduits the U- slfr'aped conduit 24 connects the top ofthe heat exchange chamber l0 with the boiler l.

The system may be charged with onia, water and hydrogen although itl is apparent to those skilled in the art that various other substances niay be used without departing from the scope of the invention. YBecause this apparatus employs the resorber principle, the solution concentration will naturally be considerably lower than that of apparatusY employing a condenser, as is well known to those skilled in the art. As suming the'apparatus to be charged with the substances indicated above, and that heat is applied the conduit 6 joins the same, absorption liquid.

will be lifted due to the gas bubbles therein from the conduit 6,"up through the Ycoil 9, conduit ll,

.cooling device l2 and into the vessel i3 from which it will how through the conduit i4 into the evaporator. From the evaporator theabsorption liquid will flow through the conduit i7 into the heat Yexchange vessel and thence through the conduit 24 into the boiler. After being heated in the boiler, the liquid will ow through the conduit 19 into the top of the absorber, and after trickling downwardly over the bailies and spilling over the top of the cylinder 22 at the .bottom portion of the absorber, will pass through the conduit 7 bach to the point where the conduit 6 :loins the conduit 7;thus completing the cycle. llt is to be noted that there is only one circuit of absorption liquid, although there arerfour diiferent concentrations in four different parts of this circuit, refrigerant being added to the absorption liquid in erent degrees at 12 and 8 and removed therefrom at l and l5. inasmuch as therefrigt will evaporate from the solution in the evaporator into the inert gas and be absorbed from the inert gas in the absorber the inert gas will begin to circulate under the influence-of gravity in accorce with well-@own principles.

Now, al basic feature of the single circuit type vapparatus such as is here disclosed, is'that the absorption liquid which Viiows through the evaporator, must begmuch 'stronger as it passes to the evaporator than when supplied tothe absorber for otherwise the refrigerant could not evaporatejntothe inert gas;i in the evaporator l5 at a lower temperature than that at which it is absorbed in the: absorber 8 and no refrigerating eect could be'produced.

The apparatus shown. on the right hand side of the drawing, that is the boiler l, the vessel l0 with the coil 9 therein, the cooling device l2 and the small gasrseparating chamber i3, together with the connecting conduits, provides means for, weakening'the absorption solution supplied to the absorber and for strengthening that supplied to the evaporator. These parts Yof the apparatus also provide means for causing the absorption liquid to circulate through its entire circuit. The present invention provides a novel and ingenious way for accomplishing thesefresults. The absorption liquid passing downwardly through the left hand leg of the conduit i7 connected to the evaporator is the coldest of any portion of the absorption liquid during operation of the apparatus, this liquid coming directly from the evaporator. Compared to it, the liquid leaving the absorber in the conduit 7 is quite warm. Besides, the liquid in the conduit 7 is heated by heat exchange with the conduit 19 and by the addition of warm gas from the conduit 6, so that by the time it reaches the coil 9, it is Yquite warm. The absorption liquid inthe coil 9 contains bubbles of gas which it is desired to have absorbed in the liquid, but absorption cannot readily take place if this coil is warm. By bringing this liquid into heat exchange relation in the vessel lllv with the cold'absorption liquid coming from the evaporator through conduit 17, two objects are obtained. In the nrst place, itis possible to cause the absorption liquid in the conduit 7 and coil 9 to becomeivery rich by picking up large amounts of refrigerant supplied to conduit 7 by the conduit 6, without the. necessity of a large heat radiating surface, a comparatively small .air-cooled coil, such as is indicated at l2 being sumcient foro the purpose. a addition to this, heat economy may be Veffected by pre-heating the absorption liquid passing from the evaporator through conduit i7 to the boiler and in this way a certain amount of refrigerant gas is expelled from the cold solution in nthe vessel lo before this solution passes through the boiler, this expelled gas passing through the conduit i8 into the conduit 6.

A further advantage of the present arrangement results from the fact that by causingbubbles of gas'entering the conduit 'I from the conduit 6 to displacea quantity of liquid therein, the absorption liquid is carried into the cooling device i2'which is located at the highest part of this system, so that the absorption liquid may iiow by gravity from there throughout the re- Vmainder of its circuit.

Y tion supplied thereto through the conduit i9. I

The solution strengthened somewhat in the absorber 8, may pass through the conduit 7, becoming mixed with more refrigerant gas as it does so and absorbing this gas as it flows through the coil 9, the conduit ll andthe cooling device l l2, although these devices (referred to above as the resorberltare at the same or a higher temperature than theiabsorber 8. Any refrigerant not absorbed in the coil 9, pipe il and cooling device l2 may pass through the conduit 23 back to theV absorber. To supply the refrigerant gas to strengthen this solution on its way from the absorber to the evaporator, the boiler l and vessel 10 are used, these devices at theV same time weakening the solution passing. to the absorber.

lt is obvious that many changes may be made in the system and method without departing from the yspirit of the inventionor the scope of the annexed cla.

l c: i e

l. in a refrigerating system of the continuous type the combination with a nr of vessels comprising a boiler, an absorber, a resorber and an evaporator of means for circulating 'a liquid Ughalloisaidlsin- .in a portion Y 1,975,860 cluding a number of conduits connecting said vessels -in series, 'a portion of the resorber being' in heat exchange relation withA the con- 'duit conveying liquid to the boiler, and means for conveying gas from the conduit conveying liquid to the boiler to the conduit conveying liquid to the resorber.

2. A ref-rigerating process comprising the steps of circulating an absorption liquid in a cycle between four vessels connected in said vessels constituting a boiler, an absorber, a resorber and an evaporator, causing the liquid to absorb rerigerant gas in the absorber and resorber, causing the refrigerant gas to be expelled from the liquid in the boiler and evaporator conveying the gas expelled inthe boiler to the resorber, conveying the gas expelled in the evaporator to the absorber, bringing warm refrigerant laden liquid of the resorber into heat exchange relation with the colder refrigerant laden liquid passing to the boiler thereby causing the expulsion of some refrigerant gas from the liquid flowing'to the boiler before it reaches the boiler and conveying ,the refrigerant gas so expelled into contact with the liquid flowing to the resorber.

V3. A refrigerating process comprising the steps of circulating an absorption liquid in a. cycle between four devices connected in series, said devices constituting a boiler an absorber, a resorbe'r andan evaporator, causing the liquid to absorb refrigerant gas in the absorber and resorber, causing the refrigerant gas to be expelled from the liquid in the boiler and evaporator, conveying the gas expelled in the evaporator to the absorber, bringing the warm refrigerant laden liquid passing' through a portion ofthe resorber into heat exchange relation with the colder refrigerant laden liquid passing to the boiler thereby cooling the liquid flowing through the resorber and thus A facilitating the absorption of refrigerant gas in the resorber, and thereby also causing the expulsion of some refrigerant gas from the liquid iiowing to the boiler before it reaches the boiler, and conveying the refrigerant gas so expelled into Contact with the liquid flowing to the resorber. KURT V. NESSEIMANN. 

